Process for producing hydroxy-aluminum nitrate polymer

ABSTRACT

Hydroxy-aluminum nitrate polymer is produced by reacting aluminum nitrate and aluminum powder in an aqueous reaction medium. The hydroxy-aluminum nitrate polymer is useful for consolidating soil in secondary oil recovery and for reducing the caking tendency of ammonium salt compositions.

United States Patent Hodgson Dec. 16, 1975 [5 PROCESS FOR PRODUCING3,783,053 1 1974 Oettmeier et al 149/46 HYDROXY ALUMINUM NITRATE3,816,590 6/1974 Huska et a] 423/ 125 POLYMER Clive Hodgson, ForestKnolls, Calif.

Chevron Research Company, San Francisco, Calif.

Filed: Apr. 8, 1974 Appl. No.: 458,632

Inventor:

Assignee:

US. Cl 423/394; 423/395 Int. Cl. C01B 21/40 Field of Search 423/394,395, 396, 111,

References Cited UNITED STATES PATENTS 7/l969 Cook 149/46 OTHERPUBLICATIONS Pauling, L., Nature of the Chemical Band, New York, 1960,pp. 344-350 & 558-559.

Primary ExaminerWalter R. Satterfield Attorney, Agent, or Firm.l. A.Buchanan, Jr.; John Stoner, Jr.; Raymond Owyang 8 Claims, No DrawingsPROCESS FOR PRODUCING HYDROXY-ALUMINUM NITRATE POLYMER BACKGROUND OF THEINVENTION Hydroxy-aluminum polymers can be prepared by the controlledaddition of an alkali metal base, e.g., Sodium hydroxide, to an aqueoussolution of a water-soluble aluminum salt. It is believed that when thebase is added to an aluminum salt solution, Ol-l ions link the Al ionstogether forming stable rings composed of six A1 atoms per unit. Whenthe molar ratio of Ol-l/Al is in the range of 0 to 2.1, the reactioninvolves the formation of single units of compositions [Al (Ol-l) ordouble units [MAUI-U221. With ratios from 2.25 to 2.7, the additional OHreacts with these simple units and forms a continuous series of higherpolymers.

The nature of hydroxy-aluminum polymers and their preparation arediscussed by P. H. Hsu and T. F. Bates, in Soil Science Society ofAmerica Proceedings, 28, No. 6, 763-769 1964), and in Formation of X-rayAmorphous and Crystalline Aluminum I-Iydroxides, Mineralogical Magazine,33, 749-768 (1964).

Hydroxy aluminum polymers are used for soil consolidation in secondaryoil recovery, as disclosed, for example, in US. Pat. No. 3,603,399,issued Sept. 7, 1971, to M. G. Reed.

l-lydroxy aluminum polymers are also used as additives in ammonium saltcompositions to reduce caking tendency and to improve hardness, asdisclosed in US. Ser. No. 323,571, of G. R. I-lawkes et a1, filed Jan.15, 1973, now US. Pat. No. 3,852,055.

SUMMARY OF THE INVENTION It has now been found that hydroxy-aluminumnitrate polymer is produced by reacting aluminum nitrate and aluminumpowder in aqueous solution. Although it is not desired to be bound byany particular theory, the approximate stoichiometry of the reactionappears to be U K OH low/1+) 3)(3I|I1-Hl) a NO wherein a can vary from 0to 1.85. It is appreciated, of course, than when a is 0, no Al reactantis present. Therefore, a preferably varies from about 0.1 to 1.85, morepreferably from 0.3 to 1.7, and most preferably from 1.0 to 1.7.

DESCRIPTION OF PREFERRED EMBODIMENTS The aluminum nitrate reactant issuitably anhydrous aluminum nitrate or hydrated aluminum nitrate.Largely because of commercial availability, aluminum nitrate nonahydrateis preferred.

In general any commercially available grade of aluminum powder ofreasonable purity is suitably employed. Suitable aluminum particle sizesare in the range -10 mesh to +325 mesh, preferably from about mesh to+60 mesh.

The molar ratio of aluminum powder to aluminum nitrate suitably variesfrom about 0. 1:1 to 1.85:1, preferably from about 0.3:1 to 1.721, andmost preferably from 1:1 to 1.7:1.

The process of the invention is conducted in an aqueous reaction medium.Generally, from about 2 mols to 1000 mols of water per mol of aluminumnitrate is employed, although from about 10 to 100 mols of water per molof aluminum nitrate is preferred.

In a modification of, the process, urea is added as a reaction componentto suppress the emission of the nitrogen oxide formed in the process ofthe invention. The urea is employed in amounts of up to 2 mols per molof aluminum metal, although amounts of urea from about 0.1 to 1.25 molsper mol of aluminum metal are preferred. The suppression of nitrogenoxides with urea is disclosed by B. A. Kerns, I&EC Process DesignDevelopment, a) 4, p. 263, 1965.

A variety of procedures can be employed for contacting the reactants. Inone modification, the entire amounts of reactants are charged to areactor and maintained at reaction conditions for the desired reactionperiod. In another modification, one reactant is added to the otherreaction components in increments. as by adding urea to an aqueousmixture of aluminum nitrate and aluminum powder. By any modification,the process is most efficiently conducted at elevated temperatures. Ingeneral, temperatures varying from about 50 to 150C. are satisfactory,with temperatures from about to C. being preferred. The most preferredreaction temperature is the boiling point of the reaction mixture, i.e.,reflux temperature. Atmospheric, subato'mospheric or superatmosphericpressures are suitably employed, although it is generally mostconvenient to employ atmospheric reaction pressure. Reaction times, ofcourse, depend in part upon the molar ratio of reactants, and in partupon the reaction temperature and pressure. Generally, however,

reaction times varying from 1 hour to 24 hours are satisfactory.

The aqueous product mixture of hydroxy-aluminum nitrate polymer issuitable for most applications. such as in fertilizers or in soilconsolidation. without further purification. However. if desired, theproduct mixture can be evaporated to give more concentrated solutions orsolid products.

The aluminum to hydroxyl molar ratio of the hydroxy-aluminum nitratepolymer depends largely upon the molar ratio of aluminum nitrate toaluminum powder employed in the process. Generally, the preferred molarratio of aluminum to hydroxyl is from about 1:1 to 112.6, and morepreferably from 1:2 to 112.6.

EXAMPLE TABLE I HydroxyAluminum Polymer Analvsis Experi- Reactant MolRatios OH/Al men! No. Urea/ANN Al/ANN 7: Al Ratio 3 TABLE l-continuedHydroxyAluminum Polymer Analvsis What is claimed is:

l. A process for producing hydroxy-aluminum nitrate having an aluminumto hydroxyl ratio of from 1:1 to 12.6 by reacting aluminum nitrate andpowdered aluminum metal. wherein the molar ratio of aluminum nitrate toaluminum varies from about 1:0.l to 1:1.85.

4 in an aqueous reaction medium of about 1 mol to [000 mols water permol of aluminum nitrate, at a temperature of 50 to 150C.

2. The process of claim 1 wherein the molar ratio of aluminum tohydroxyl in the hydroxy-aluminum nitrate varies from about l:2 to 12.6.

3. The process of claim 1 wherein up to urea per mol of aluminum metalis emplo additional reaction component.

4. The process of claim 1 wherein the aluminum nitrate is aluminumnitrate nonahydrate.

5. The process of claim I wherein the temperature varies from to 125C.

6. The process of claim 1 wherein the aluminum powder has a particlesize in the range 10 mesh to +325 mesh.

7. The process of claim 2 wherein l0 mols to mols water per mol aluminumnitrate is employed.

8. The process of claim 3 wherein l0 mols to 100 mols water per molaluminum nitrate is employed.

2 mols of 'ed as an

1. A PROCESS FOR PRODUCING HYDROXY-ALUMINUM NITRATE HAVING AN ALUMINUMTO HYDROXYL RATIO OF FROM 1:1 TO 1:2.6 BY REACTING ALUMINUM NITRATE ANDPOWDERED ALUMINUM METAL, WHEREIN THE MOLAR RATIO OF ALUMINUM NITRATE TOALUMINUM VARIES FROM ABOUT 1:0.1 TO 1:1.85, IN AN AQUEOUS REACTIONMEDIUM OF ABOUT 1 MOL TO 1000 MOLS WATER PER MOL OF ALUMINUM NITRATE, ATA TEMPERATURE OF 50* TO 150*C.
 2. The process of claim 1 wherein themolar ratio of aluminum to hydroxyl in the hydroxy-aluminum nitratevaries from about 1:2 to 1:2.6.
 3. The process of claim 1 wherein up to2 mols of urea per mol of aluminum metal is employed as an additionalreaction component.
 4. The process of claim 1 wherein the aluminumnitrate is aluminum nitrate nonahydrate.
 5. The process of claim 1wherein the temperature varies from 75* to 125*C.
 6. The process ofclaim 1 wherein the aluminum powder has a particle size in the range -10mesh to +325 mesh.
 7. The process of claim 2 wherein 10 mols to 100 molswater per mol aluminum nitrate is employed.
 8. The process of claim 3wherein 10 mols to 100 mols water per mol aluminum nitrate is employed.